The impact of clinical history on mammographic interpretations.

OBJECTIVE To determine whether mammographic interpretations are biased by the patient's clinical history. DESIGN On 2 occasions, separated by a 5-month wash-out period, 10 radiologists read mammograms for the same 100 women, randomly divided into 2 groups of 50. For 1 group, the clinical history was supplied for the first reading and omitted (except for age) for the second reading. This sequence was reversed in the other group. In addition, 5 cases were shown a third time with a deliberately leading sham history. PATIENTS Selected with stratified random sampling from 3 categories of diagnostic findings (64 had mammographic abnormalities) and from the definitive designation of breast cancer or no breast cancer (18 had breast cancer). MAIN OUTCOME MEASURES Radiologists' diagnostic accuracy and directional changes in interpretations and recommendations between the 2 readings. RESULTS The direction suggested by the history led to small but consistent changes in the interpretations. Overall diagnostic accuracy was not altered, but recommendations were affected for appropriate further diagnostic workup: an alerting history (eg, breast symptoms or family history of breast cancer) increased the number of workups recommended in patients without cancer (P=.01); and a nonalerting history led to fewer recommended workups in the cancer patients (P=.02). The direction of the sham histories led an average of 4 of the 10 radiologists to change previous diagnoses and an average of 1 radiologist to change a previous biopsy recommendation. CONCLUSIONS Knowledge of the clinical history may alter a radiologist's level of diagnostic suspicion without improving performance in either diagnosis or management recommendations.